Titanium is used in many applications due to its relatively low weight and strengthening properties. For example, titanium can be mixed with one or more other metals to produce different types of titanium metal alloys. Such titanium alloys are widely used in different types of applications because of their good combinations of strength, toughness, and formability.
Atoms of pure titanium align in the solid state in either a hexagonal close-packed crystalline structure, called the alpha (α) phase, or a body-centered cubic structure, called the beta (β) phase. In a pure metal, transformation from the alpha to the beta phase occurs upon heating above a temperature such as 883° C. Most alloying elements either stabilize the alpha phase to higher temperatures or stabilize the beta phase to lower temperatures. For example, Aluminum (Al) and oxygen are typical alpha-stabilizing elements, and typical beta-stabilizing elements are vanadium (V), iron (Fe), molybdenum (Mo), nickel (Ni), palladium (Pd), niobium (Nb), silicon (Si), and chromium (Cr). A few other alloying elements, such as tin (Sn) and zirconium (Zr), have little effect on phase stabilization.
The lowest temperature at which a 100-percent beta phase can exist is called the beta transus; this can range from 700° C. (1,300° F.) to as high as 1,050° C. (1,900° F.), depending on alloy composition. Final mechanical working and heat treatments of titanium alloys are generally conducted below the beta transus temperature in order to achieve the proper microstructural phase distribution.